1. Technical Field
The present disclosure relates to an electrolytic capacitor having a conductive polymer layer, and a production method therefor.
2. Description of the Related Art
In recent years, with a decrease in the size and the weight of electronic instruments, small-sized and large-capacitance capacitors for high frequencies have been desired. As such capacitors, developments have been advanced about electrolytic capacitors small equivalent series resistance (ESR) and excellent in frequency properties. Electrolytic capacitors each include an anode body including a valve metal such as tantalum, niobium, titanium or aluminum, a dielectric layer formed on the anode body, and a cathode body. Out of these electrolytic capacitors, the following are also called solid electrolytic capacitors: electrolytic capacitors in each of which a conductive polymer layer containing a conductive polymer layer (solid electrolytic layer) is formed as a cathode member on a dielectric layer.
In order to heighten strength of the conductive polymer layer, investigations have been made about the use of a crosslinking agent when the conductive polymer layer is formed. For example, according to Japanese Translation No. 2012-517113 of PCT Publication, a conductive polymer layer (polymer outer layer) is formed by: forming a solid electrolytic layer containing a conductive polymer; immersing this layer into a solution containing a crosslinking agent and then drying the layer; and immersing the layer into a liquid dispersion containing a conductive polymer and then drying the layer. According to Japanese Translation No. 2012-517113 of PCT Publication, in order to restrain the conductive polymer layer of a capacitor element from being peeled off and make the conductive polymer layer high in performance of covering terminal portions of the capacitor element, the crosslinking agent is used before the formation of the polymer outer layer, as described above.